Electric multiple outlet



P 10, 1940- R. s. PENNOCK ET AL 2,214,065 ELECTRIC MULTIPLE OUTLET Filed July 18, 1938 2 Sheets-Sheet l pt- 0, 1940. R. s. PENNOCK arm.

ELECTRIC MULTIPLE OUTLET Filed July 18, 1938 2 Sheets-Sheet 2 Patented Sept. 10, 1940 UNITED STATES PATENT OFFICE ELECTRIC MULTIPLE OUTLET York Application July 18, 1938, Serial No. 219,746

3 Claims.

This invention relates to multiple outlets, for installation in the permanent electric wiring systems of buildings to receive and coact with a like plurality of multi-bladed plugs attached to re- 5 spective extension-cords or the like.

While multiple outlets very commonly have their fixed contacts along each side integrally connected together so that two wires, respectively connected to the two side-strips of contacts, may

serve all of the stations, wiring necessities sometimes make it desirable that each station be a separate one individually served by its own particular pair of wires; and in other instances it is desirable that one side of all of the stations be served by a common, single wire but that on the other side each station shall have its two or more contacts individually isolated and each connected with a separate service-wire.

In commercial practice it is customary for manufacturers to factory-build multiple-outlet devices particularized to each of these three types of wiring which may, for convenience, be called common supply and return, separate supply and return and common-supply separate-return types, in the sequence above described.

A general object of the present invention is to provide a novel and advantageous multiple-outlet structure which, as marketed, will be suitable for common supply and return type of installation, but which the electrician may very readily and satisfactorily alter, on the job, to serve the needs of either of the other two types of wiring above mentioned; thus to minimize production cost by standardizing on a single structure in lieu of three distinct ones, to lessen the stocks that jobbers and dealers must carry, and to make it unnecessary for the electrician to ascertain in advance the particular type or types of multiple outlets that must be used on a given job.

A further general object of this invention is to provide, in such a multiple-outlet structure, fixed contacts on each side thereof all interconnected electrically in single-piece construction but with the normal, unitary connections between adjoining fixed contacts on each side of the device arranged for and accessible to easy intentional break off removal without disassembling any parts of the unit, and with binding-screw provision available for each contact on both sides of the device.

Further objects of the invention are so to construct and combine the elements of the novel structure that it may be of rugged strength,

economical of manufacture, easy to assemble,

practically proof against accidental breaking oil? of any of said normal unitary connections between contacts on the same side, amply safeguarded against electrical hazards such as shortcircuiting or sparking between broken-apart 5 contacts on the same side, adapted to permit of quick and easy removal of any and all of said break-off connections as by use of ordinary pliers, and with all permanent parts of the structure securely held in proper positions regardless of 10 the presence of or the removal of the break ofi portions.

For attainment of these and other objects which will hereinafter become apparent, the present invention consists in the features of con- 15 struction and combinations of parts hereinafter set forth and claimed, reference being had to the accompanying drawings wherein we have illustrated, for purposes of full disclosure, a duplex outlet that embodies the invention in a specific 20 construction which has been found to attain the stated desirata very satisfactorily from a practical standpoint.

In the drawings:

Figure 1 is a perspective view of a duplex out- 25 let embodying this invention;

Fig. 2 is an exploded perspective view showing the casing parts, contacts and support-members in position to show details of their construction andfacility of their assembly; 30

Fig. 3 is an enlarged transverse section on line 33 of Fig. 1; and

Figs. 4, 5 and 6 are conventionalized diagrams of the several available types of wiring connections aforesaid; being respectively common sup- 35 ply and return, common-supply separatereturn, and separate supply and return.

In the embodiment of the invention shown, In indicates in general the duplex socket, illustrated in a form particularly designed for flush in- 40 stallation in connection with a wall plate (not shown), as is suggested by the plaster ear type of mounting straps II; the two-piece shell or casing 12 of the unit being molded of suitable insulating material and comprising a rather deep 45 body l3 and a complemental shallow base l4 matching it in plan-contour.

These casing members, when assembled, are secured together by a center-rivet l5 tapped as at l6 (Fig. 3) for the customary Wall-plate screw and having its squared head l1 engaged in a corresponding socket in said base; relative twisting of the two casings parts about the rivet-stem being prevented by interlocking the end portions 55 ventionally sunk to accommodate the wall plate.

Each side-wall of the insulating casing 12 is formed to provide a suitably-shaped recess 22, located between the adjoining contact-stations and preferably extending the full height of the side-wall, to expose the break off portions of 'the appropriate contact-strip and also the wirereceptive binding screws therefor, these parts being sunk a little below the side-plane of the casing but readily accessible; and further, each said recess 22 is desirably bisected by a vertical separator-rib 23, shown as extending full height of the recess, to insulate'from each other, and to aid in positioning, contiguous plate-portions of i the conductor-unit, from which the plate-connecting break off portions may be removed on occasion, as hereinafter more fully described.

Each conductor-structure 25 is herein shown as a single-piece strip, formed to provide longitudinally-separated clusters of contact-springs 25 to serve respective outlet stations; respective binding-screw plates 21 connected with said contacts and somewhat spaced apart at their adjoining edges; and narrow break off, straps 28,

bridging between the plates at their top and bottom and weakened by grooves 29 at their lines of juncture with the plate-edges.

As shown in Fig. 1, the fixed-contact unit 25, when in place in the shell, has its binding-screw plates 21 largely exposed in the wide bottom-portion 22 of the shell-Wall's recess 22 and the narrower break off straps 28 are likewise accessibly exposed but without protrusion beyond the side plane of the shell; the upper one of said straps lying in narrow top-portion 22 of recess 22, which need only be of convenient width to receive the nose of suitable pliers for breaking ofi the strap.

In the desirable construction shown, the break off straps 28 are of arched or U-shaped conformation, to straddle a separator-rib 23, which is of somewhat greater protrusion than the thickness of the binding-screw plates 21. Desirably, also, the break ofi straps diverge with respect to each other as they leave the plane of the plates, at low angles to the latter, so that they arch over the separator-rib in inclined position; but due, in part, to the weakened lines 29 thereof, they may be easily pried up to vertical relation to the plates so that they may be fully gripped with pliers to be broken oil", although their initially low angle substantially obviates accidental breaking ofi in manufacture and handling.

In marketing the unit, binding screws 32 are provided for all of the plates 21, and it will be apparent that the wiring connections of the several diagrams 6, 5 and 5 may be realized by leaving the break off straps intact and utilizing any two binding screws on opposite sides of the device for the two-wire connection of Fig. 4; or breaking ofi the straps 28 on one side only of the device and utilizing three binding screws for the wiring of Fig; 5; or, for the complete separation of circuits through the two outlets, shown in Fig.

6, removing all of the break off straps and utilizing all four binding screws.

Under conditions where some or all of the break ofi straps have been removed, as indicated in Figs. 5 and 6, it is especially desirable that the separated binding-screw plates be very securely positioned against moving toward each other and of course safeguarded against hazards of short-circuiting. Also, it is very desirable that both the electrical parts and the casing be suitable for economical production to make their advantages available at low price, and these ends are well attained in the particular construction of the contact elements and the casing as herein shown.

Desirably, for these and other purposes, the interior ofthe casing I2 is divided into four sections by the longitudinal partition 33 and the lateral partition 34, each shown as extending the full depth of the casing; matching portions of such partitions being provided on the base 14 and body 13, respectively. The junction of these partitions at the center of the structure is enlarged into a hollow post 35 through which the assembly rivet l1 passes, andthe cross partition 34 merges into the separator-ribs 23 (which in part form its edges), that fit neatly between the plates 21 of the contact strips.

On the base 14, chambers 36 snugly receive the bottom-length of the contact-strips and low cleats 31, extending longitudinally, have their ends arranged to form abutments for the 'confronting base-walls of the contact-clusters, to prevent longitudinal shifting of the latter toward each other when the break ofi connections 28 between the plates 21 have been removed; while opposite the topportion of each plate 21 the body of the casing l2 has integral bracing-cleats 38, paralleling the side-wall of the casing and reaching down behind said plates.

Thus, screw-driver pressures tending to tilt the tops of the plates backward or otherwise displace them are adequately resisted even when the break ofi straps are removed, and the wrenching of the contact strips in removing said straps does not displace the plates 21 or contactspring clusters 26. The safeguarding of the permanent electrical parts against displacement is furthered, and ease of assembly of parts is promoted, by providing on each binding-screw plate 21 top and bottom positioning-lugs, 40 and M, respectively, to engage receptive notches 60' and 4| molded respectively in body l3 and base I4 of the casing.

For strength of the construction and to interlock the body and base of the casing against relative turning about the center-rivet l5, the plaster ear members I l are formed with a relatively narrow horizontal neck 43 and wider body Mi arranged at right angles thereto, this L- shaped structure being adapted to be slipped into a shallow T-slot extending vertically in the end wall of the shell from the bottom thereof to adjacent its top; the bottom of said metal member 44 extending slightly below the bottom plane of the casing body l3 to engage in a receptive crossslot 56 in the base it. Also, the base is provided with an upstanding lug 68 abutting the outer face of metal member 44 and fitting into the narrowed outer-portion of T-slot 55, to augment the strong interlock of the parts.

While we have herein described in detail a particular embodiment of our invention that we deem highly advantageous, it will be understood that variations in details of embodiment may be having openings therein registering with the transverse portions of said T-slots and carrying upstanding lugs fitting the outward openings of said T-'slots; two casing supporting units engageable with said T-slots, each consisting of a metal strap having a wider body-portion fitting the transverse portion of a said T-slot and a narrower supporting-neck, at right angles thereto, fitting the outward opening of said T-slot and protruding at the top thereof, the free end of said strap-body extending below said casing-body and projecting into the registering opening in said base; and a single connector centrally unitingthe body and base of said casing.

2. In an electrical wiring device, a body and a base jointly providing a casing having thin side walls and thick end-walls, said body having outwardly opening T-slots extending from near the top to the bottom of its end-walls and said base havingv openings therein registering with the transverse portions of said T-slots and carrying upstanding lugs fitting the outward openings of said T-slots; two casing-supporting units engageable with said 'T- slots, each consisting of a metal strap having a wider body-portion fitting the transverse portion of a said vT-slot and having a narrower supporting-neck, at a. substantially right angle thereto, fitting the outward opening of said T-slot and protruding at the top thereof, the outer face of said strap-body abutting the adjacent upstanding lug carried by said base and the free end of said strap-body extendingbelow said casing-body and projecting into the registering opening in'said base; and a single connector centrally uniting the body and base of said casing. v

3. In a multiple-outlet unit, a two-piece insulating casing having in its face blade-openings structure;

fora number of plug-stations and in each sidewall a recess located between adjacent plugstations, each of said recesses containing a vertical separator; two longitudinally extending conductor-structures arranged within said casing adjacent said side-walls, each of said structures comprising a number of longitudinally spacedapart contacts registering with the corresponding blade-openings of said plug-stations, bindingscrew plates permanently connected respectively with said contacts and extending into adjacent ones of said'side-wall recesses and on opposite sides of said separator and integral break-off straps" means disposed substantially entirely in said recesses and spanning said separatorsand connecting adjacent ones of said plates; means including cooperating pairs of notches formed in the two pieces of said casing and engaging the edges of said plates for anchoring said plates in place independently of the remainder of said means including integral backing cleats carried by the two pieces of said casing for retaining said plates in place upon removal of said break-off connections; and means for securing together the two pieces of said casing.

ROBERT S. PENNOCK.

MARK N. RUSSELL. 

